Half to ii



(No Model.)

H. G. FORGASON.

ELECTRIC ARG LAMP.

N0. 447,767. Patented Mar. 10, 1891.

INVENTOR Hem yC fzgawam ATTORNEY.

yzimvqiy UNITED STATES HENRY O. FOR

ASON, OF OAKLAND, CALIFORNIA, ASSIGNOR OF ONE- IIALF TO H. G. COMSTOOK, OF SAlilE PLACE.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 447,767, dated March 10, 1891.

Application filed May 28, 1890. Serial No. 352,886. (No model.)

To (0 whom it may concern:

Be it known that I, HENRY O. FORGASON, a citizen of the United States, residing in Oakland, in the county of Alameda and State of California, have invented certain new and useful Improvements in Are Lamps, of which the following is a specification.

My invention relates to electric-are lamps, my improvement having special reference to the cut-out thereof. The object of my invention is to provide means whereby in a single lamp, when the carbons are exhausted, they will be bro ughtinto close contact, thus closing the are, and when a do able-carbon la mp is employed the secondary pair of carbons will do the same.

My invention consists in the construction and combination of parts, as hereinafter de scribed and claimed.

In the accompanying drawing the figure is a front elevation showing my invention complete, and so much of one common form of are lamp as is necessary to illustrate the connection and operation of my improvements.

A and A indicate the upper rods of a double-carbon lamp,and O O are the ordinary clamp-rings for lifting them. Details of the connections and means for operating the clamps are omitted, as they form no part of my invention.

Each rod A A has a reduced portion B B, respectively, at a point which, when the car bons are about exhausted, will arrive at clamp O, and since the clamp C will not then hold the rod the latter will drop and the upper carbon will rest on the lower. Thus in a single arc lamp when the carbons are exhausted the rod will drop and the circuit will be closed through the carbons without the resistance of the are. In a double-carbon lamp the secondary rod only might have the reduced portion 15'. In this case, when the primary carbons are exhausted, the current is transferred to the secondary carbons in the usual manner, and then when the latter are burned out the circuit will be closed by closing the are; but for a double-carbon lamp I have devised further improvements besides forming reduced portions in both rods. In such lamp if the primary rod A should stick at clamp O, in order that the current may be transferred to the secondary carbons by the ordinary means. If new the secondary rod should fail to feed properly, it is necessary to release the holding means of the primary rod in order to send the current therethrough, and thus relieve the ordinary cut-out as far as possible from danger. I will now proceed to describe these means.

At D is acoarse-wire magnet, the armature E of which is pivoted at F and carriesa pawl G. The primary rod A is provided with a recess H at a point, so that as the reduction B arrives at clamp O the said recess arrives 0pposite the end of pawl G, and the weight of the armature or a spring causes the pawl to enter the recess and prevent rod A from dropping farther.

At I is represented the frame of the working parts, and at L and M binding-posts.

N is the armature, pivoted at n of the cutout coil P, and is connected to magnet D by wire J, and carries contact-plate 0.

K is a plate connected with the magnet D and with the binding-post L. Above plate 0 is fixed contact O, connected with the coarse-- wire coil of magnet P. An adjusting-screw a is located under armature-lever N.

Q is a fine wire connecting post M with the fine-wire shunt of magnet P, and R is a connection from the metallic framel to the coarse wire of magnet P.

Of course other partssuch as the upper parts of rods A A and binding-post Mare insulated from the frame, the current being supplied to the carbon rods in any ordinary manner.

In operation, if the primary rod fails to feed, the current will be, as usual, transferred to the secondary set, and when the latter carbons are exhausted the circuit will be closed through the unburned portions of the carbons, owing to the reduced portions 13 allowing red A to drop, through the clamp, thus closing the are and allowing the lamp to go out without using the ordinary cut-out at all;

feed it will cut itself out in the ordinary way.

This immediately energizes magnet D, owing to the shunt-magnet attracting armature N, closing contacts 0 0, and the current passing from magnet P through the contacts 0 0, part of lever N, wire J, magnet D, and the line at binding-post L. The magnet D being thus energized attracts armature E, releases pawl G, and allows the primary rod A to drop and close the circuit through the primary carbons. This immediately relieves the ordinary cutout; but this, of course, does not occur while the secondary side is in order and burning; but should the necessity arise for the cut-out said cut-out will at once trip the pawl, and thus cut itself out before it has had time to be injured. I

To distinguish from the ordinary or present cut-out in use, and which I also use, I term my improvement the gravity cut-out, among the advantages of which are the following:

If a lamp is insufficiently trimmed, the gravity cut-out automatically closes the circuit through the arc, thus offering a path of low resistance for the current without danger to the lamp and without loss of energy. If either of the rods stick when the other is consumed, the gravity cut-out closes the are on the consumed side and prevents the opening of the circuit. If a lamp is left untrimmed, the dynamo may be started and stopped repeatedly Without danger to the lamp, for there is no break in the lamp.

When lamps are in places inaccessible to the trimmer, as in stores or factories on Sundays while they are closed, the lamps may be left untrimmed for several days without danger, thus saving the lamps and the expense of a pair of carbons.

Small and therefore cheap carbons may be used, especially in all-night lamps during the summer months, for in case they should burn out about daylight the gravity cut-out closes the circuit and there is no loss but the loss of light for a few minutes.

If a careless trimmer fails to visit a lamp, the gravity cut-out will close the circuit and no loss follows but that of light, which would occur, together with loss of energy and the great liability to burn out the lamp, through defective contacts of the shunt cut-out now in use.

In lamps using the present style of cut-out I shunt it often happens that the contact-points are defective, or that there is an unusual mechanical resistance to the armature, which, when the lamp is about exhausted, will cause the arc to blaze, thus injuring the rods and magnet in the main cut-out circuit, a second magnet for operating the auxiliary cut-out, and a contact operated by the first-mentioned magnet for energizing the second magnet, whereby the main cut-out may be cut out by the auxiliary, substantially as described.

2. In a double-carbon lamp, the combination, with lifting-clamps, of the carbon-carrying rods having reduced portions, one of said rods having also a locking device adapted to be released by magnetic action, substantially as described.

3. In a double-carbon arc lamp, the combination, with lifting-clamps, of the carbon-carrying rods having reduced portions, one of said rods having also a recess, a pawl for engaging said recess, and a magnet in the gut-out circuit for releasing said pawl from the recess, substantially as described.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

- HENRY G. FORGASON. \Vitnesses:

STEPHEN R. Wool), H. L. ADAMS. 

